1. Field of the Invention
The present invention relates to material handling, and in particular, to equipment and methods for facilitating removal of finished rolls after rewinding.
2. Description of Related Art
Sheet material made of paper, plastic or other materials is manufactured in a web that is wound into a relatively large roll. In many instances, this roll is too large for use in other manufacturing processes. For that reason, the web is often unwound and rewound into smaller rolls. In some cases, the web is slit into a plurality of webs that are then simultaneously wound into a number of axially shorter rolls.
A difficulty with such rewinding is the labor involved with removing finished, rewound rolls. These rolls may be relatively heavy and require special handling equipment. Also, the finished rolls may be distributed on a number of separate mandrels and special techniques are needed to remove these rolls in an orderly fashion.
In U.S. Pat. No. 4,611,769 a slitter feeds strips to one of the shafts on a turnstile. After a group of rolls is wound, the turnstile moves the shaft to an unloading position where the shaft is retracted to allow the rolls to fall onto an unloading plate. The retracted shaft is later moved with the turnstile to a loading position and redeployed to penetrate the centers of a fresh batch of empty cores. This arrangement is only satisfactory for relatively lightweight rolls that can be swung by a turnstile and later allowed to fall as a winding shaft retracts.
U.S. Pat. No. 3,845,915 shows a cantilevered shaft that is axially movable for either positioning or ejecting a roll. An ejected roll can fall "onto a hoisting device which then transports the roll out of the machine." Column 3, lines 33-34. This reference has little disclosure on the unloading of the rolls.
In U.S. Pat. No. 5,217,177 strips are wound on spindles that are mounted on a revolver. A loaded spindle can be taken off the revolver by a turret to a station where a comb can pull the rolls off the spindle while new cores are loaded from the opposite end. The spindle does not axially retract.
In U.S. Pat. No. 5,620,151 a slitter feeds a rewinder. When a complete roll is wound, a lifter rises to support the roll. After contact with the roll is detected, chucks disengage the roll, which is then lowered to a carriage that carries the roll from the machine. This reference does not disclose techniques for axially shifting the rolls.
In U.S. Pat. No. 4,346,852 a table moves between a core loading station and a station for winding and discharging rolls. When a roll is wound, holding devices are released and the rolls are lowered by receivers. Again, this reference does not disclose techniques for axially shifting the rolls.
For devices that lower a roll on swing arms, see U.S. Pat. Nos. 4,508,283; 4,749,140; 5,356,087; and 5,445,341. For a device that lowers a roll on hoisting hooks, see U.S. Pat. No. 5,121,885.
See also U.S. Pat. Nos. 4,458,853; and 5,782,425.